Four months after publicly announcing his desire to bring the United Soccer League to Oakland as part of a joint-development project with the Oakland Athletics, Mark Hall said he’s now exclusively focused on building an 18,000-seat stadium in Concord.

The Walnut Creek-based real estate developer penned an open letter to Oakland Mayor Libby Schaaf and city council members in March, describing an ambitious plan that would provide the Oakland Coliseum complex with a new soccer and baseball stadium. That idea, however, has been scrapped with several political obstacles standing in the way.

Instead, Hall wants to bring his USL expansion franchise to a lot near the Concord BART station. A motion allowing “advanced exploration” of the proposal was passed by Concord’s city council in late May, but the city remains in the reviewal stage and hasn’t formally approved the project.

“[The project] also includes a convention center and a couple of hotels and some additional housing on the downtown Concord BART station,” Hall said. “That’s something we’re working on with both BART and the city of Concord, who are the primary land owners.”

According to a Concord council spokesperson, no permit application has been filled out and no future meetings regarding the initiative are currently scheduled. Hall will need to get approval from BART in addition to the city council in order to acquire the land necessary for his proposed stadium.

Hall’s firm is working on graphic visualizations for the stadium and its surrounding developments. He said those should be available in the next couple of months.

The gamble with building a soccer stadium in Concord is getting fans from across the East Bay to attend matches. The city seemingly offers a less built-in core market for a team, but Hall claimed being just steps from BART would alleviate that concern and bring in a wide swath of soccer enthusiasts. He’s also confident youth soccer participation in the area can translate to a larger-than-expected fanbase.

“We’re really confident about [attracting the whole East Bay],” Hall said. “There were a lot of people who questioned Concord but have never even been to Concord and have not been to the downtown and seen how much Concord has improved over the last 10 or 15 years. It’s really a beautiful environment.”

Oakland A’s president Dave Kaval is also the president of the San Jose Earthquakes in the MLS, perhaps damaging a potential partnership between the baseball team and a soccer proposal such as the one led by Hall.

Multiple Oakland officials said keeping the A’s in the city and figuring out where they can build a new ballpark is the top sports development priority, though Oakland director of economic development Mark Sawicki said in a statement that he was “open to considering other viable self-financed sports proposals, like soccer, in the future.”

With his USL East Bay team hoping to debut in 2021, Hall decided Concord was a better, more realistic site for his organization.

“We have looked at locations across the East Bay,” Hall said. “They were aggressively pursuing us from the very beginning and we’re very, very excited about it.”